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6 changes: 6 additions & 0 deletions properties/P000122.md
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Expand Up @@ -21,3 +21,9 @@ $\mathbb R^0=\{0\}$ is an isolated point.

The closely related {P123} property is
defined on page 316 of {{zb:0951.54001}} and on page 38 of {{mr:2766102}}.

----
#### Meta-properties

- This property is preserved by finite products.
- This property is preserved by arbitrary disjoint unions.
1 change: 1 addition & 0 deletions properties/P000184.md
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Expand Up @@ -16,3 +16,4 @@ Per Theorems 1.1.2 and 1.11.4 of {{zb:0401.54029}}, this is equivalent to being
#### Meta-properties

- This property is hereditary.
- This property is preserved by finite products.
14 changes: 14 additions & 0 deletions spaces/S000224/README.md
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---
uid: S000224
name: Torus
refs:
- wikipedia: Torus
name: Torus on Wikipedia
---

The product space {S170} $\times$ {S170}.

Equivalently, the quotient of
$[0,1]^2$ obtained by identifying $(x,0)\sim(x,1)$ and $(0,y)\sim(1,y)$.

Homer Simpson's favourite food.
7 changes: 7 additions & 0 deletions spaces/S000224/properties/P000016.md
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---
space: S000224
property: P000016
value: true
---

$X$ is the square of {S170} and {S170|P16}.
7 changes: 7 additions & 0 deletions spaces/S000224/properties/P000037.md
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---
space: S000224
property: P000037
value: true
---

$X$ is the square of {S170} and {S170|P37}.
7 changes: 7 additions & 0 deletions spaces/S000224/properties/P000065.md
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---
space: S000224
property: P000065
value: true
---

Immediate from the definitions.
7 changes: 7 additions & 0 deletions spaces/S000224/properties/P000089.md
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---
space: S000224
property: P000089
value: false
---

The the function $(z,w)\mapsto(-z,w)$ is continuous self-map with no fixed points.
7 changes: 7 additions & 0 deletions spaces/S000224/properties/P000122.md
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---
space: S000224
property: P000122
value: true
---

$X$ is the square of {S170} and {S170|P122}.
7 changes: 7 additions & 0 deletions spaces/S000224/properties/P000155.md
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---
space: S000224
property: P000155
value: false
---

Since {S170|P155}, $X$ is locally homeomorph to {S176}, which is not homeomorph to {S25}.
10 changes: 10 additions & 0 deletions spaces/S000224/properties/P000184.md
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---
space: S000224
property: P000184
value: true
refs:
- wikipedia: Torus
name: Torus on Wikipedia
---

$X$ is the square of {S170} and {S170|P16}.
10 changes: 10 additions & 0 deletions spaces/S000224/properties/P000200.md
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---
space: S000224
property: P000200
value: false
refs:
- zb: "1044.55001"
name: Algebraic Topology (Hatcher)
---

We have $\pi_1(X)\cong\pi_1(S^1\times S^1) \equiv \pi_1(S^1)\times \pi_1(S^1)\cong \mathbb{Z}\times\mathbb{Z}$.
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